(a) Field of the Invention
The present invention relates to an optical module. More particularly, the present invention relates to an optical module that transfers an electric signal that is generated according to an applied optical signal to a circuit board.
(b) Description of the Related Art
In general, in a low speed system, a connection between circuit boards and between chips or between systems is performed through a metal electrical cable. However, as in a next generation information communication system that is formed with a large capacity parallel computer or an ATM switching system having a capacity of 1 Tb/s or more, as a large amount of information is transmitted and transmission speed is improved, when using such a metal cable, an electrical problem such as skew and electromagnetic interference (EMI) occurs and thus operation efficiency of the system is deteriorated and it is difficult to integrate a system.
Therefore, technology that performs an optical connection using an optical transmitting/receiving module has been developed, and a method of directly coupling an optical receiving element to a ribbon optical fiber multichannel optical connector having a reflector that is located with a tilt angle of 45° with an optical coupling method within the optical transmitting/receiving module, a method of coupling an optical transmitting/receiving element to a polymer optical waveguide having a reflector that is located with a tilt angle of 45° and connecting the polymer optical waveguide to a multichannel optical connector, a method of vertically coupling an optical transmitting/receiving element to a polymer optical waveguide and connecting the polymer optical waveguide to a multichannel optical connector, and a method of vertically coupling an optical transmitting/receiving element that is fixed to a plastic package to a multichannel optical connector are used. In this case, as an optical transmitting element, i.e., an optical source, a Vertical Cavity Surface Emitting Laser (VCSEL) array is used, and as optical receiving element, i.e., an optical detector, a photodiode (PD) array is used.
A conventional optical module reflects light that is oscillated through a light emitting port by 90° by an optical waveguide and transfers the light to an optical fiber that is connected to an optical connector along a core that is formed in a board. “ParaBIT-1: 60-Gb/s-Throughput Parallel Optical Interconnect Module, presenter: N. Usui” that was published in ECTC 2000 in May of 2000 has a structure in which a 24 channel polymer waveguide film in which a plane reflector is located with a tilt angle of 45° and a 24-optical fiber BF connector are connected, and the waveguide film and the connector are manually assembled.
In this technology, because a method of coupling an optical transmitting/receiving element to a polymer optical waveguide having a reflector that is located with a tilt angle of 45° and connecting a polymer optical waveguide to a multichannel optical connector may relatively easily form a reflector and house an optical coupler, an optical switch, and a Wavelength Division Multiplexing (WDM) element in a polymer optical waveguide, the method can extend a function of an entire module and is thus evaluated as a very effective method.
However, in order to produce an optical transmitting/receiving module for parallel optical connection having an extending function, when using the optical coupling technology, even if a small misalignment occurs in coupling of the optical transmitting/receiving element and an optical fiber, a large optical coupling loss occurs and thus satisfactory efficiency is not obtained. Therefore, structure enhancement of an optical transmitting/receiving module for parallel optical connection that can minimize a coupling loss is urgently requested.